In recent years there has been increased interest in reclaiming aluminum cans, such as those used for soft drinks and beer. At reclamation distribution locations the cans are crushed or flattened to reduce the volume for shipment. The can crushers, as used in the past, have generally consisted of a large rubber-covered drum that cooperated with a rotating steel drum having angle-shaped blades. The cans are introduced into the area between the drums and the angle-shaped blades moved the cans into the nip between the drums where the cans were crushed or flattened. Can crushers of this type have had certain disadvantages. The rubber-covered drum was readily damaged by sharp materials thereby requiring down time for maintenance and repair.
More recently, can crushers of the type shown in U.S. Pat. No. 4,358,995, have been used. Crushers of the type shown in the aforementioned patent application, include a rotatable polygonal-shaped drum composed of a series of flat outer surfaces. Sharpened blades are mounted flatwise on each surface and project circumferentially beyond the respective surface.
In crushers of this type, the cans to be crushed are introduced into the area between the drum and a spring loaded pressure plate, and on rotation of the drum, the blades engage the cans and move the cans into the nip between the drum and the plate to crush or flatten the cans.
While can crushers of the type described in the aforementioned patent application have been very successful in crushing or compacting aluminum cans, there has been a need to further increase the compacted density of the cans to reduce the volume of the cans for shipment. In the past, the compacted cans have been trucked from the reclamation site to a baler where the cans are further compressed into bales and then shipped to the refineries. By providing denser, more fully compressed cans, the crushed cans can be transported directly to the refinery by truck, which eliminates the operation of baling.
At the reclamation sites it has also been found that a portion of the cans being reclaimed contain material, such as liquid, dirt, stones, or the like, which increases the weight of the can being reclaimed and thus increases the amount paid to the person returning the cans. Not only does the contained material provide a false indication of the weight of aluminum, but dirt and other foreign materials in the cans can cause serious abrasion problems to the crushing rolls or drums used in the crushing apparatus, and dirt, once crushed into the can, causes contamination in the remelting process.